Eric Hahn writes:
[I've already replied in detail to Eric privately.]
I've come up with this SWAHBI (like a SWAG, but an idea
instead of a guess).
Hm, "silly, wild *ssed, half-baked idea" ? That's not an acronym I've
seen before.:)
What I'm looking for is the following two items for *all*
Mersenne numbers 2^p-1 where p is prime and p>1:
1) All known factors (including, but not limited to,
the smallest known factor (noted if it isn't))
My data contains some prime exponents with as many as eight known
prime factors.
2) Largest potential factor attempted
I have this as well, but there are also some gaps in the trial
factoring efforts to date, which I also keep track of and try to
close.
I ask that the two items are human-readable at the
very least.
The format I use is described in the mersfmt.txt file; it is human
readable, being primarily alphanumeric plus parentheses and colon (:).
Conversion to just about any other printable format is easy; UNIX has
lots of tools that allow this sort of text manipulation.
I've pulled a couple of files off mersenne.org
(FACTORS.ZIP and NOFACTOR.ZIP) as well as off
Alex Kruppa's page. While the files appear complete
as far as I can tell, they only cover the ranges
of p between 11 - 9,999,991 and 33,219,281 - 35,999,993.
Correct. George has still not asked me for my data for exponents
above 10 million, but it's probably almost as easy to retest as to
have me send (my data isn't very deep for the exponents above 21
million or so), and makes for a good double check.
They also don't cover *all* known factors!
Correct; since GIMPS is mainly looking for Mersenne primes, Prime95
stops at the smallest factor (which is not always the first factor it
finds for an exponent because of the 16 pass approach in the sieving
code).
Any and all information on the ranges between 10M - 33.22M and
above 36M is greatly appreciated, as well as any known factors not
listed in the files I've pulled.
My prime exponent data for all ranges is now about 111 MB; this
includes all known factors, each exponent's largest attempted trial
factor, and all the ECM and P-1 effort (but no P-1 save files). The
gaps data is another 9MB, and the P-1 save files, mostly from
Factor98, are about another 110 MB. All but the P-1 save files use
the format described in:
http://www.garlic.com/~wedgingt/mersfmt.txt
... which is human readable and accepted by the mers package programs.
The P-1 save files are understood by the mers package's extract enough
to print most everything but the "residue" itself, including the beta
release's extract understanding the new P-1 save file format of George
Woltman's Prime95 v19. Extract's understanding of the P-1 save file
formats will be extended, when I get around to it, to converting from
one P-1 format to another.
Conrad Curry writes:
Will Edgington maintains this information, but it may be
hundreds of megabytes in size. If a website, such as
Entropia, has the space it will be useful to make this database
available (in many small compressed files) so that others may
use it.
Yes, but the first problem is that my 56Kb modem is in the way.:(
But I would be willing to upload it a range at a time over a month or
so, going back to the start to update ranges that have changed since
their last upload, if someone out there has enough web disk space
for it.
And what GIMPS needs, the list of prime exponents with some data but
no known factors, is still quite small, especially in the binary
DATABASE format (which extract can print in the mersfmt.txt format);
that DATABASE file for all prime exponents with data but no factors is
only 2MB presently. It is produced by the contract program during my
updates and put in the mersdata.{zip,tgz,tar.gz} file.
Eric Hahn writes:
If no information is known where p>100M, then what can I do??
I have some data for exponents over 2^31. The smallest prime exponent
with no data is only 21556027 presently (though I increase it some
with every update), however, and most of the data is below that.
Also, generating new data for a given prime exponent under about 2^60
(if your machine has an eight byte integer type available in C) or so
is easy using mersfacgmp; all it takes is CPU time.
Will
http://www.garlic.com/~wedgingt/mersenne.html
mers.tgz
mers.tar.gz
mers.zip
mersfmt.txt
mersdata.tgz
mersdata.tar.gz
mersdata.zip
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